Combined fuel vaporizer and torch



R. C. PIVONKA COMBINED FUEL VAPORIZER AND TORCH Dec. 12, 1967 2 Sheets-Sheet Filed Aug. 24, 1965 INVENTOR RALPH c. PIVONKA BY Wily/QM ATTORNEY Dec. 12, 1967 R. c. PIVONKA COMBINED FUEL VAPORIZER AND TORCH 2 Sheets-Shet 2 Filed Aug. 24, 1965 INVENTOR RALPH C. PIVONKA ATTORNEY United States Patent Ofiice 3,357,474 Patented Dec, 12, 196'? 3,357,474 COMBENED FUEL VAPOREZER AND TORCH Ralph C. Pivot-lira, Flame Engineering (30., La (Irosse, Karts. 67548 Filed Aug. 24, 1965, Ser. No. 482,032. 2 (Ilairns. (Cl. 153-53) ABSTRACT OF TI-m DISCLOSURE The subject invention comprises an elongated vaporizer including concentric spaced tubes having a liquid inlet into the central tube at its rear end, the liquid traveling centrally therethrough to the forward end of the vaporizer and thence to the rear end of the vaporizer through an annular vaporizing space between the tubes extending the entire length of the vaporizer. The forward end of the outer tube is closed and spaced slightly from the forward end of the inner tube, and the rear end of the outer tube is closed with respect to the inner tube to seal off the rear end of the annular vaporizing space. A heat conductive helical member is disposed in the annular space to facilitate heat transfer from the outer tube to the annular space, to effectively increase the length of fluid travel therethrough, and to centrifugally swirl relatively dense unvaporized fluid into contact with the outer tube.

A plurality of nozzles are symmetrically disposed about the rear end of the vaporizer and have fluid communication with the rear end of the annular vaporizer space, such nozzles being directed forwardly in spaced parallelism to the vaporizer, and a generally cylindrical flame holder is disposed in concentric spaced relation about the rear end of the vaporizer and the nozzles, such flame holder having a forwardly extending length substantially less than that of the vaporizer so the vaporizer extends into a region of intense heat and temperature forwardly of the flame holder.

This invention relates to new and useful improvements in burners which vaporize or convert vaporizable fuel into a vapor or gaseous form, emit such vapor or gaseous fuel from a nozzle for subsequent combustion with a portion of the heating effect of such combustion being utilized in the conversion of vaporizing of the fuel.

An important object of the present invention is to provide a burner of the general character defined above that will result in efficient combustion of fuel over a Wide range of fuel delivery rates for a given size burner.

Still another important object of the present invention is to provide a burner of the character defined above which will enable the burning of fuel at a very high rate in relation to the size of the burner.

et another important object of the invention is to provide a burner of the character defined above in which the burner accepting only a portion of the vaporizing section thereof operates at a cool temperature, whereby even a manually operated fuel control valve can be positioned in the fuel line very close to the burner so that only a very short time delay occurs between a change in valve position and a burning rate even on turning the supply of fuel off.

Another object closely allied to the object of the preceding paragraph is to provide a burner such that on turning the same off. only a very small amount of residual heat is transferred to the fuel supply line and contents thereof.

Other important objects of the invention reside in the provision of a burner of the class defined above wherein ready disassembly and reassembly is possible for the purpose of repair or replacement of parts and for such cleaning the interior of the same.

A final important object to be specifically enumerated is to provide a burner of the character defined above which is inexpensive to manufacture and rugged, durable and dependable in operation.

An important feature of the invention resides in the provision of the vaporizer such that the same may be readily disassembled for cleaning, and wherein fuel being vaporized is caused to flow along a helical path against the interior of an exteriorly heated member so that unvaporized and hence more dense liquid fuel components are preferentially urged by centrifugal action against the interior of a heated wall so as to assure efficient and rapid vaporization.

Still another important feature of the invention resides in the nozzles having removable closure members, preferably closure plugs whereby access can be gained conveniently to the interior of the nozzles for any necessary cleaning and for opening or freeing the orifice from any obstructive material.

Another important feature of the invention resides in the provision of a cup-shaped orifice defining device, whereby an orifice plate constituting the base of such cup-shaped device can be accurately positioned and secured a predetermined distance from the outlet end of the nozzle. It is preferred that the orifice in itself be circular in transverse configuration with the inlet end of the same being cylindrical and of lesser diameter than the outlet cylindrical portion of the orifice.

A final important feature to be specifically enumerated resides in the outer sleeve or flame holder being comprised of a hollow cylindrical shell or sleeve having the rear thereof crimped or swedged at angularly spaced locations to be secured to the vaporizer, at position intermediate the positions at which the nozzles are secured to the vaporizer.

An important aspect of the invention resides in structure comprising a nozzle arranged to emit fuel supplied thereto in a forward direction, an elongated flame holder embracing said nozzle in spaced relation thereto and disposed with its forward end forwardly of the nozzle, an elongated vaporizer disposed in parallelism to the flame holder, said vaporizer being disposed laterally of the nozzle and extending forwardly of the forward end of the flame holder to terminate in a free end thereof, with at least one-third of the extent of the vaporizer forwardly of the nozzle being forwardly of the flame holder, whereby at least a substantial portion of the vaporizer is forwardly of the flame holder and is directly exposed to the heating effect of burning fuel, said vaporizer comprising concentrically spaced inner and outer tubular members with the forward ends thereof being respectively open and closed and with said members being connected adjacent their rear ends to close the space therebetween, whereby an annular space is defined between the members having communication with the interior of the inner member through the forward end of the latter, a helically shaped member disposed in the annular space and embracing the inner member for imparting a helical travel path to fluids passing rearwardly through the annular space, whereby centrifugal action tends to urge preferentially unvaporized fuel radially outward against the outer member, passageway means communicating between the annular space adjacent the rear end of the vaporizer and the nozzle for supplying fuel to the latter, and means at the rear end of the inner member for connecting the latfor to a source of vaporizable fuel.

Another important aspect of the invention involves structure comprising a generally cylindrical nozzle shell having front and rear ends, an orifice plate in the shell adjacent the front end thereof closing the front end of the shell, said orifice plate having an orifice therethrough, a threaded closure member, said shell being threaded adjacent the rear end thereof with said closure member and chamber therebetween in the shell, means for vaporizing fuel, and passageway means extending laterally through the shell intermediate the closure member and the orifice plate for providing fluid communication between said vaporizing means and said chamber. This aspect of the invention also preferably includes the orifice plate being provided with a peripheral flange extending toward the front end of the shell and substantially coterminous therewith.

Still another aspect of the invention involves structure Comprising a vaporizer including an elongated tubular member concentrically received in spaced relation within a hollow cylindrical sleeve, said member having front and rear ends, a plurality of nozzles equiangularly spaced at -a uniform radius about and attached to the tubular member adjacent the rear end of the latter with each of said nozzles being arranged to emit vaporized fuel in a direction toward the front end of said tubular member, said sleeve having an internal radius substantially greater than the radial extent of the nozzles from the axis of the sleeve, said sleeve having front and rear ends, passageway means for establishing fluid communication radially from the interior of the tubular member to the nozzles, and means equal in number to the number of nozzles angularly spaced about the tubular member and connecting the latter at positions angularly intermediate circumferentially successive nozzles to the rear end of the cylindrical sleeve.

A final aspect of the invention to be specifically described involves a burner for vaporizable fuel comprising a straight tubular member having front and rear ends, a pair of nozzles secured to the tubular member in diametrically opposed positions on the outside of the latter, a generally cylindrical sleeve coaxially disposed about the tubular member in radially spaced relation to the latter and the nozzles, said sleeve including an integral rear end section having radially inwardly inclined positions that are diametrically opposed and secured to the tubular member at positions circumferentially intermediate the nozzles, a tube concentrically disposed in spaced relation within the tubular member to define an annularspace therebetween, said tubular member being closed at its frontend and sealingly secured adjacent its rear end to the tube, said nozzles being arranged to discharge vaporized fuel towards the front end of the tubular member, and passageway means for fiuid communication between the annular space and thenozzles.

Other objects, features and aspects of the invention will become apparent during the following description of a preferred embodiment of the invention, such description to be taken in conjunction with the accompanying drawings illustrative of the preferred embodiment of the invention, wherein:

FIGURE 1 is an isometric view of the invention taken from the front end of the same, with certain portions of the structure being broken away and with hidden details of the structure being shown in dashed outline;

FIG. 2 is an isometric view of the structure shown in FIGURE 1, this view being taken from the rear of the burner and with certain hidden details of the structure being shown in dashed outline;

FIGURE 3 is a central, longitudinal sectional view of the structures shown in FIGURES 1 and 2, this view being taken upon the plane of the nozzles, and with portions of the helical member being shown in dashed outline;

FIGURE 4 is a longitudinal sectional view of the structure shown in FIGURE 3, this view being taken upon a plane at right angles to the view of FIGURE 3;

FIGURE 5 is a front elevational view of the burner; FIGURE 6 is an enlarged sectional detail view taken centrally of one of the nozzles; and

FIGURE 7 is an exploded isometric view on an enlarged scale of a nozzle assembly, a portion of the cupshaped orifice device being broken away to expose the orifice.

Referring now to the drawings, wherein like numerals designate like parts throughout the various views, the reference numeral 10 designates the burner generally, the

same being comprised of a vaporizer assembly designated generally at 12,.nozzle assemblies designated generally at 14 and 16, and a flame holder or shield designated generally at 18.

The vaporizer. 12 is comprised of an elongated and straight tubular member that is closed at its front end as indicated at 22, and a straight tube 24 concentrically disposed in the tubular member 20 in spaced relation thereto, it being noted that the front end 26 of the tube 24 is spaced axially a short interval rearwardly of the closed front end 22 of the tubular member 29. The rear end of the tubular member 20 is externally threaded, not shown, and is effectively provided with a rearward extension that takes the form of a conventional internally threaded coupling 28 that is tightly threaded upon the external threads at the rear end of the tubular member 20, the arrangement being such that the tubular member 20 and the coupling 28 constitute a unitary construction, and if desired or deemed expedient, the forward end of the coupling 28 can be welded to the tubular member 20. Jointly, the tubular member 20 and the coupling 28 comprise or constitute a tubular body having a rear end that is internally threaded.

The rear end of the tube 24 is externally threaded and tightly threaded into a conventional coupling 30 (the latter being modified as hereinafter), and rigidly fixed thereto by means of welding or brazing indicated at 32 (see FIGURES 3 and 4).

Prior to securing the tube 24 to the conventional coupling 30 as described above, the conventional internally threaded coupling 30 is modified by externally threading the end of such coupling 30 on the end thereof into which the tube 24 is received as indicated at 34, such external threading 34 on the coupling 30 being such as to mate with the internal threads 36 with the conventional pipe coupling 28. Such construction enables convenient assembly and disassembly of the tubular member 20 and the tube 24 by simply screwing the coupling 30 into and out from the coupling 28, it being noted that the threaded connection between the coupling members 28 and 30 serves to seal the rear end of an annular space 38 defined between the tube 24 and the tubular member 20.

The vaporizer 12 additionally includes a helical member 40 disposed within the annular space 38 and embracing the tube 24. Preferably, the helical member 40 is in the form of a length of wire snugly wrapped about the tube 24 so as to be frictionally retained thereon and so as to remain therewith during insertion of the removal of the tube 24 from within the tubular member 20. So that such insertion and removal of the helical member 40 from the tubular member 20 can be most easily accomplished, the wire comprising the helical member 40 is preferably of a diameter slightly less than the radially separation of the tube 24 from the tubular member 20 so that a sliding fit between the helical member 40 and the interior of the tubular member 20 is realized. While the helicalmember 40 can extend the entire axial extent of the annular space 33, such an extent is not necessary, and in the preferred construction the helical member 40 has an axial extent that is approximately coincident with the forward half of the axial extent of the tube 24. In order to positively assure that the helical member 40 retains a relatively fixed position with respect to the tube 24, the helical member 40 can if deemed necessary or expedient be brazed to the tube 24 at its extremities and at spaced intervals or even continuously along its length of engagement with the tube 24. While certainly not essential to attainment of the primary function of the helical member 40 which will be described subsequently, the helical member 40 can if desired have an overall or outside diameter such that portions of the same are in contact with the internal surface of the tubular member 20 so as to establish a low thermal resistance path between the tubular member and the tube 24, such being desirable from the standpoint of achieving an enhanced heat exchange between the tubular member 29 and the tube 24, it being understood that the helical member is preferably metallic so as to have a reasonably high degree of thermal conductivity. While the helical member 40 is shown as being wound from a material of circular cross section, such is not essential, and as will be readily understood by those skilled in the art, the helical member 40 can be wound from a wire or metallic strip of substantially rectangular cross section, whereby the area of contact of the helical member 40 with the tube 24 can be enhanced as well as when such is desired the area of contact between the helical member 40 and the internal surface of the tubular member 26.

The character of the nozzle assemblies 14 and 16 will be best appreciated upon reference to FIGURE 7 which shows the nozzle assembly 14 in exploded form, and it will be appreciated inasmuch-as the nozzle assemblies are identical that a detailed description of the nozzle assembly 14 will suffice for both. The nozzle assembly 14 comprises a hollow-cylindrical body or shell 59, the rear end of which is normally closed at its rear end by an externally threaded plug or closure wall 52 that is threadingly and removably received in the rear end of the cylindrical shell 50, the latter being provided with internal threads such as those indicated at 54. In practice, it, has been found convenient to employ aconventional pipe coupling (modified as hereinafter described) as the hollow cylindrical shell 50, in which case the plug 52 can be a conventional or standard pipe plug. When a conventional internally threaded pipe coupling is employed as the hollow cylindrical body or shell 50, the end of the same remote from the plug 52 is cylindrically reamed for a short interval as indicated at 56 in FIGURE 7.

A cup-shaped orifice device 60 is provided which is comprised of a flat circular orifice plate 62 having an integral peripheral flange 64 that in itself defines a short hollow cylinder having an external diameter approximately equal to the internal diameter of the cylindrical interior 56 of the shell 50. The axial extent of the cylindrical interior 56 of the shell 50 is at least as great as the axial extent of the flange 64 and is preferably identical thereto so that the threads 54 remaining after reaming the cylindrical surface 56 constitute a stop such that when the device 69 is inserted into the shell 50 the axial extremity 66 of the device 60 coincides with the end 68 of the shell 50. The device 60 can be mounted in the shell 50 so that the extremity 66 of the flange coincides with the end 68 of the shell 50 in two different ways, namely, the same can be sized so as to require a tight press fit within the shell St), or alternatively, as preferred, the device 60 is positioned in the body of shell 50, and a head of welding 70 is applied about the juncture of the flange 64 and the body 50 at the end 68 of the latter as best shown in FIGURE 6. The press fitting mode of assembly of the device 60 affords the advantage should the need ever arise that the device 60 can be punched from the sh ll 50 and replaced, such punching operation being possible on removal of the plug 52. The welding technique is preferred notwithstanding the advantage of a press fitting for the reason that any necessity for replacement of the orifice device 60 is unlikely and the welding affords the degree of permanence such that the device 60 is denied any susceptibility to dislodgment that could possibly occur during overzealous efforts to clean orifice 72 provided centrally of the orifice plate 62 portion of the device 60.

In the preferred construction, the orifice 72 is not simply a cylindrical sharp edged opening through the orifice plate 62, but rather is constituted of an opening that through approximately one-half the thickness of the orifice plate 62 is of a cylindrical configuration of a relatively small diameter at the side of the orifice plate 62 adjacent the plug 52, and the other half of the axial extent of the opening, namely, the portion on the side of the orifice plate 62 remote from the plug 52 is of a cylindrical configuration of relatively greater diameter. To describe cylindrical portions of the orifice 72 of relatively smaller and lesser diameters are indicated respectively at 74 and 76 in FIG- URES 61and 7.

The nozzle assemblies 14 and 16 are positioned flush against diametrically opposed sides of the tubular member 20 adjacent the rear end of the latter and welded thereto as indicated at 78 and 80. After the cylindrical shells of the nozzle assemblies 14 and 16 have been welded to the tubular member 20, an opening (see FIG- URES 3, 4 and 6) is drilled entirely through the cylindrical shell 50, entirely through the tubular member 20 (with the tube 24 removed during such drilling), and into the hollow interior of the nozzle assembly 16 through one side of the hollow cylindrical shell thereof, whereby openings 82 and 84 are provided for respectively providing communication between the annular space 38 and the nozzle chambers 86 and 83. After the above described drilling to provide the openings 82 and 84 has been completed, the opening through the side of the cylindrical shell 50 remote from the tubular member 20 is Welded closed as indicated at 90 in FIGURE 3.

As thus-far described, it will be evident that the nozzle assemblies 14 and 16 are rigidly fixed insofar as their cylindrical shells are concerned with respect to the tubular member 20, and that such hollow cylindrical shells are in excellent heat exchange relation with the tubular member 20 by virtue of the welding 78 and 80. It will be noted that the welding 78 and 80 not only provide the described heat exchange relationship, but also prevent or close off the openings 82 and 84 from any external leakage in the region that the nozzle assemblies 14 and 16 abut the tubular member 26 prior to the welding.

It will also be apparent as thus far described that any gas or vapors introduced into the nozzle assemblies 14 and 16 through the openings 82 and 84 will be emitted or discharged from the nozzle assemblies 14 and 16 through the respective orifices of such assemblies in a direction parallel to the longitudinal extent of the tubular member 29 from a position spaced substantially rearwardly from the forward end 22 of the tubular member 26, and that the nozzle assemblies 14 and 16 are spaced in close proximity to the rear end of the tubular member 20'.

The flame holder or shield 18 is comprised substantially of a hollow cylindrical wall or sleeve that is concentrically disposed about the tubular member 20, such cylindrical sleeve having an internal radius substantially greater than the radial extent of the nozzle assemblies 14 and 16 from the access of the tubular member 20 as clearly shown in FIGURES 3 and 4. Adjacent the rear end of the cylindrical sleeve 1% the same is radially and rearwardly inclined at diametrically opposed portions 162 and 164, the arrangement being such that such diametrically opposed portions of the sleeve 100 at their radially innermost and rear extent terminate against or in very close proximity to diametrically opposed portions on the tubular member 20 at which position the flame holder of the shield 18 is welded to the tubular member 20 as indicated at 196 and 108, it being noted that such welding affords an eflicient heat exchange between the flame holder or shield 18 and the tubular member 20. As best shown in FIGURES 2 and 5, the portions 106 and 108 at which the shield 18 is welded to the tubular member 20 are angularly interposed about the circumference of the tubular member 20 intermediate the nozzle assemblies 14 and 16, and it will also be apparent upon inspection of such figures that the periphery of the rear extremity of the shield 18 is generally of a figure eight configuration with the loops thereof such as indicated at 110 and 112 are of such a size and position as to radially surround the nozzle assemblies 14 and 16 with considerable spacing there between. It will also be apparent from inspection of the drawings that the rearmost extremity of the shield 18 is preferably disposed intermediate the axial extent of the nozzle assemblies 14 and 16.

The flame holder or shield 18 can be conveniently and economically fabricated from a short length of cylindrical steel pipe or tubing upon simply swedging, hammering or gripping between appropriately shaped jaws of a vice to define the inclined portions 102 and 104 prior to welding the shield 18 to the tubular member 24. It will be obvious that the shield 18 is attached to the tubular member 20 after the nozzle assemblies 14 and 16 have been attached and the openings 82 and 84 made.

In the preferred construction, the forward extremity of the shield 18 is substantially rearward of the forward end 22 of the tubular member 20. Indeed, it is preferred that at least about A to /3 and desirably about /2 of the axial extent of the tube 20 forwardly of the nozzle assemblies 14 and 16 be also forward of the forward terminus of the shield 18. Preferably, the axial extent of the helical member 40 is such as to be essentially coincident with the axial extent of the tubular member 20 forwardly of the forward end of the shield 18, though as mentioned previously the helical member 40 can be of greater extent.

The operation of the burner will be readily understood. The internally threaded rear end of the coupling member 30 affords a convenient means for attaching the burner 10 to a valved supply of vaporizable fuel under pressure, not shown, vaporizable fuels such as liquid propane, butane or mixtures thereof, commonly known as LPG fuelsl being especially well suited for use in conjunction with the burner 10.

Liquid vaporizable fuel introduced into the burner 10 through the coupling 30 passed forwardly through the tube 24 to emerge through the end 26 of the latter, and thence pass rearwardly through the annular space 38 to the openings 82 and 84 from which the fuel passes radially into the nozzle chambers 86 and 88 and thence outwardly through the orifice of the nozzle assemblies 14 and 16 wherethey are ignited. Such fuels are highly combustible and are easily ignited, and will after being ignited with fuel being supplied at a very low rate produce flame in which a portion or all of the axial extent of the tubular member is engulfed whereby the fuel within the annular space 38 becomes warmed and vaporization is initiated and fuel at least partially in a vapor form is emitted with considerable force toward the front end of the burner 10. Such process is accumulative in the sense of tending to accelerate the rate of heat transfer to the tubular member 20 and its contents, and eventually and in fact in a very short interval of time normal burner operation is reached. Such normal burner operation includes slowly fueltvapor or gasses entering the nozzle chambers 86 and 88 from whence they are emitted with considerable force through the orifices of such nozzle assemblies. The specific form of the orifices previously described coupled with the orifice plates being effectively recessed within the forward ends of the hollow shells of the nozzle assemblies (by virtue of the peripheral flanges on the orifice plates), and efficient admixture of such emitted vapors or gasses with air entering through the rear of the shield 18 occurs with such fuel air mixture passing forwardly through the shield 18 toward the front end of the burner 10. In normal operation of the burner 10, the actual flame front is established at a position generally corresponding with the forward end of the shield 18 over a wide range of fuel burning rates. It has been observed in actual use of the described and illustrated burner 10 that the apparatus results in attainment of a nearly constant fuelair ratio throughout an extraordinarily wide range of fuel burning rates, so that a very efficient combustion of the fuel is obtained that is neither excessively lean or rich.

Flames of a substantially high velocity propogate forwardly with considerable force from the flame front, that is from a position axially in the vicinity of the forward end of the shield 18, and the forward end portion of the tubular member 20 is emersed in such flames. Consequently, heat is rapidly transferred to the forward end portion of the tubular member 20 and to the an: nular space 38 therein. This results in liquid fuel emerging from the forward end 26 of the tube 24 immediately contacting the hot interior surface of the tubular member 20 and thence passing rearwardly of the annular space 38 for continued exposure to the heated inner surface of the tubular member 20. The exposure of unvaporized liquid to the heat of the interior surface of the tubular member 20 is greatly enhanced by the provision of the helical member 40 in that the latter compels fluids passing rearwardly through the annular space 38 to travel a distance substantially greater than the axial extent of the helical member 40 and most importantly also forces such fluids to travel a helical path such that the denser components such as unvaporized droplets are hurled radially outwardly by centrifugal force into direct contact with the heated internal surface of the tubular member 20. This arrangement makes for a highly eflicient vaporization of a vaporizable fuel and virtually assures not only that all portions of the fuel are vaporized so as to avoid any spitting or flutter in the constancy of the flame, but also assures the vapor or gasses being more or less uniformly heated in temperature while achieving these results without the vapors or gasses having and necessity for being heated to excessively high temperatures.

The vaporizing operation described above results in the burner 10 achieving normal burner. operation within a very short time interval after initially cracking the valve to admit fuel, and also enables the burner 10 to be turned off quickly as may be necessary under some circumstances of use as for safety reasons, etc.

One important advantage of the described and illustrated structure is that excepting only the forward end portion of the tubular member 20 and the forward end portion of the shield 18, the burner 10 is at a low temperature at most only exceeding ambient temperatures to a modest extent during burner operation, whereby valve equipment including manual valves if desired can be positioned closely adjacent the inlet end of the burner 10 with the control for such valves remaining at temperatures even during high fuel combustion rates such that the same can be manipulated by the operator without fear of burning his hands. It is quite advantageous to locate a control valve closely adjacent the inlet of the burner 10 in that shutting off the burner only a small amount of fuel must be consumed before all burning ceases.-

Inasmuch as the shield 18 and the nozzle assemblies 14 and 16 do not become heated to high temperatures (excepting only the forward end portion of the shield 18) during burner operation, the heat exchange between such structural components and the tubular member 20 is advantageous on turning off the burner inasmuch as it constitutes effectively a heat sump tending to prevent the heat from the forward end portion of the tubular member 20 from passing rearwardly through the coupling 30 and to any structure wherein liquid fuel is contained.

Although other materials can be used in constructing the illustrated and described structure, it has been found that all components thereof can be made of steel and for the most part of conventional steel piping and standard fixtures therefor. The helical member 40 can also be steel, and if desired can be of any suitable metal having a higher heat conductivity such as brass, copper or the like.

In addition to the advantages of burner 10 enabling efficient combustion over a wide range of fuel supply rates whereby high temperature flame and combustion products are directed with considerable force in a well defined direction, the burner possesses important advantages with respect to durability and ruggedness, simplicity in construction and utilization, and by being virtually maintenance free. To the extent that maintenance is required, such will consist essentially solely of cleaning. While the interior of the tubular member has no tendency to coke or collect foreign matter which might tend to clog the flow of fluids through the annular space 38, the same can nevertheless be cleaned upon unscrewing the tube 24 and removing the same from the tubular member 20. Upon such removal of the tube 24 the interior tubular member 24 as well as the openings 82 and 84 are readily accessible for cleaning and dislodgment of any foreign matter. Also, with the tube 24 removed, the exterior and interior of the latter as well as the helical member 40 can be readily cleaned and then replaced in the tubular member 20.

The plugs such as the plug 52 of the nozzle assembly 14 can be removed whereby the hollow cylindrical shell can be cleaned and the orifice 72 freed of any foreign matter that might tend to clog the same. Also, removal of the plug 52 affords convenient access to the opening 82 for cleaning of the latter, as will be evident.

As will be clear to those skilled in the art, the coaxial arrangement of the vaporizer 12 and the shield 18 together with the symmetrical positioning of the plurality of nozzle units about the vaporizer intermediate to the latter and the shield greatly contributes to the compactness of the structure, while contributing to an economy of weight without any sacrifice of necessary strength. It will also be noted that the coupling member 30 enables the burner 10 to be coupled directly to and in alignment with a fuel supply line, whereby the fuel supply line is situated as remotely as possible from the direction of flame and combustion product propagation, and it will also be noted that the burner 10 is such as to be supported by and directed by such a fuel supply line, not shown, connected to the burner 10 by means of the coupling member 30.

Manifestly, the illustrated and described preferred embodiment of the invention is susceptible to numerous variations and modifications without departing from the spirit of the invention; the illustrated embodiment of the invention having been described in great detail in order to assure a full and complete understanding of the principles of the invention. Accordingly, attention is directed to the appended claims in order to ascertain the actual scope of the invention.

I claim:

1. A burner for vaporizable fuel comprising a straight tubular member having front and rear ends, a pair of nozzles secured to the tubular member in diametrically opposed positions on the outside of the latter, a generally cylindrical sleeve coaxially disposed about the tubular member in radially spaced relation to the latter and the nozzles, said sleeve including an integral rear end section having radially inwardly inclined portions that are diametrically opposed and secured to the tubular member at positions circumferentially intermediate the nozzles, a tube concentrically disposed in spaced relation Within the tubular member to define an annular space therebetween, said tubular member being closed at its front end and sealingly secured adjacent its rear end to the tube, said nozzles being arranged to discharge vaporized fuel toward the front end of the tubular member, and passageway means for fluid communication between the annular space and the nozzles.

2. In a burner for vaporizable fuels, structure comprising a vaporizer including an elongated tubular member concentrically received in spaced relation within a hollow cylindrical sleeve, said member having front and rear ends, a plurality of nozzles equiangularly spaced at a uniform radius about and attached to the tubular member adjacent the rear end of the latter with each of said nozzles being arranged to emit vaporized fuel in a direction toward the front end of said tubular member, said sleeve having an internal radius substantially greater than the radial extent of the nozzles from the axis of the sleeve, said sleeve having front and rear ends, passageway means for establishing fluid communication radially from the interior of the tubular member to the nozzles, and means equal in number to the number of nozzles angularly spaced about the tubular member and connecting the latter at positions angularly intermediate circumferentially successive nozzles to the rear end of the cylindrical sleeve, said last means comprising an integral rear end portion of the sleeve being radially inwardly inclined at circumferentially spaced positions to terminate at locations disposed about the tubular member intermediate adjacent pairs of said nozzles, and said sleeve being fixed to the tubular member at such locations.

References Cited UNITED STATES PATENTS 654,566 7/1900 Gustafson 158-33 666,538 1/1901 Loeben. 868,084 10/1907 Gogel 158-33 893,668 7/1908 Stanley 158-53 1,135,072 4/1915 Swanson 158-33 1,240,117 9/1917 Blackwell 15 8-33 1,289,222 12/1918 Mettlin 158-53 1,493,886 5/1924 Lawrence 15 8-53 1,503,642 8/1924 Dayton 158-53 1,749,248 3/1930 Houlis 158-53 1,879,938 9/1932 Lambert 158-53 1,928,898 10/1933 Kelley 158-71 2,144,491 1/ 1939 Heberlein 158-79 X 2,263,908 11/1941 Strawn 158-33 X 2,870,825 1/ 1959 Schoenwald 158-5 3 2,888,028 5/1959 Hill 239-596 X FOREIGN PATENTS 8,644 3/1908 France. 47,709 5/ 1909 Switzerland.

FREDERICK L. MATTESON, 111., Primary Examiner. ROBERT A. DUA, Examiner. 

1. A BURNER FOR VAPORIZABLE FUEL COMPRISING A STRAIGHT TUBULAR MEMBER HAVING FRONT AND REAR ENDS, A PAIR OF NOZZLES SECURED TO THE TUBULAR MEMBER IN DIAMETRICALLY OPPOSED POSITIONS ON THE OUTSIDE OF THE LATTER A GENERALLY CYLINDRICAL SLEEVE COAXIALLY DISPOSED ABOUT THE TUBULAR MEMBER IN RADIALLY SPACED RELATION TO THE LATTER AND THE NOZZLES, SAID SLEEVE INCLUDING AN INTERGRAL REAR END SECTION HAVING RADIALLY INWARLDY INCLINED PORTIONS THAT ARE DIAMETRICALLY OPPOSED AND SECURED TO THE TUBULAR MEMBER AT POSITIONS CIRCUMFERENTIALLY INTERMEDITATE THE NOZZLES, A TUBE CONCENTRICALLY DISPOSED IN SPACED RELATION WITHIN THE TUBULAR MEMBER TO DEFINE AN ANNULAR SPACE THEREBETWEEN, SAID TUBULAR MEMBER BEING CLOSED AT ITS FRONT END AND SEALINGLY SECURED ADJACENT ITS REAR END TO THE TUBE, SAID NOZZLES BEING ARRANGED TO DISCHARGE VAPORIZED FUEL TOWARD THE FRONT END OF THE TUBULAR MEMBER, AND PASSAGEWAY MEANS FOR FLUID COMMUNICATION BETWEEN THE ANNULAR SPACE AND THE NOZZLES. 